This invention relates to methods and apparatus for discriminating between the front and back surfaces of developed films.
The discrimination of the front and back surfaces of developed films in prior techniques was done by visually finding figures recorded on the films or by a manual judgement such as directly touching the films by hand. Such discrimination methods may always result in an inaccurate judegment, and particularly, the discrimination of the front and back surfaces of a mounted film (or slide film) which is fitted to a mount was very difficult. In addition, it will be necessary to take dirt or dust, or thermal deformation of the developed film into consideration as well as errors in assembling or working machine parts of an optical system for discriminating the surface (front or back) of the film.